This relates to imaging devices, and more particularly, to image sensor pixels having dual conversion gain functionality.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an image sensor includes an array of image pixels arranged in pixel rows and pixel columns. Circuitry may be coupled to each pixel column for reading out image signals from the image pixels.
Typical image pixels include a photodiode for generating charge in response to incident light. Image pixels may include a dual conversion gain switch that allows the pixel to operate in a high conversion gain mode in low light conditions in which increased sensitivity is desired, and to operate in a low conversion gain mode in high light conditions in which increased charge storage capacity is desired. In some instances, it may be desirable to use the increased charge storage capacity provided by the dual conversion gain circuitry even when the pixel is being operated in the high conversion gain mode. While the dual conversion gain switch can be turned on to access the increased charge storage capacity of the pixel, this may increase the dark current and noise associated with the pixel.
It would therefore be desirable to be able to provide imaging devices with improved image sensor pixels.